RFXPulse module + Photo sensor vs RFXPwr module

Post by **xanhoera** » Mon Apr 06, 2009 8:28 pm

To monitor my electricity usage, I'm in a situation where I can choose between a RFXPulse module + Photo sensor (I have a red led blinking) or a RFXPwr module. Is there anything that might benefit the one more than the other?

As far as I can calculate the price does make a difference. But I don't want to find out that for example the photo sensor is less accurate than using the rfxpwr module.

./

Post by **b_weijenberg** » Mon Apr 06, 2009 8:34 pm

The photo sensor will measure the pulses from the utility meter and the result is as accurate as this meter.

If the utility meter doesn't have a blinking LED or if you want to measure the power usage on each power phase select the RFXPwr. Otherwise you can select the cheaper photo sensor + RFXPulse.

Post by **Digit** » Mon Apr 06, 2009 8:50 pm

You can also use RFXPulse with a DIN rail KWh meter with S0 output.

Post by **Willem4ever** » Mon Apr 06, 2009 8:55 pm

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<br />You can also use RFXPulse with a DIN rail KWh meter with S0 output.
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Good I was planning on doing that. Ordered a RFXpulse yesterday evening

Post by **Bastiaan** » Tue Apr 07, 2009 1:45 am

Laat je even weten welke KWh meter je hebt gekocht? Zit met dezelfde overweging hier. (3 fasen)

Post by **Lennart** » Tue Apr 07, 2009 9:02 am

For monitoring my solar panels (three systems, each on its own phase), I also opted for DIN rail kWh meters with S0 output. I prefer the direct connection between the kWh meters and the RFXPulse, instead of going the indirect (more analog) kWh meter -> visible light -> photo diode -> RFXPulse route. It also saves you the hassle with exact positioning, tape that may come loose and accidentally ripping of the sensor (which makes you miss some pulses as well).

For monitoring my power usage, I use the RFXPwr with current sensor. I would have prefered kWh meters with S0 output and RFXPulse here as well for accuracy, but it just won't fit in my fusebox (no slots left on the DIN rail).

The kWh meters I use are Shellcount meters with an analog display, bought from Conrad. I can't find them anymore in their webshop (they do have Shellcount analog meters available, but they are quite expensive now). A nice meter with an LCD display may be article nr. 125348 - 89. A similar one under Conrad's own Voltcraft brand is 125363 - 89.

Note however that these meters may vary in the number of pulses per kWh (2000, 1000 or 500) and their internal power consumption (0,5 W or more) in general, so check before you buy. The more pulses per kWh, the higher your measuring resolution/accuracy in general (but at a certain point the sending interval of the RFXMeter is the limiting factor). The Shellcount meter above has 2000 pulses / kWh and a power consumption of < 0.6 W.

As far as connecting the S0 bus to an RFXPulse goes: just connect it to the blue and copper wire of an open ended RFXPulse cable. No need to apply external voltage or anything.

Lennart

Post by **Lennart** » Tue Apr 07, 2009 9:16 am

Another affordable meter is mentioned in:

http://www.domoticaforum.eu/topic.asp?TOPIC_ID=999 (note that this meter has 1000 pulses / kWh)

And one more thing: check the main fuse (For 3 phases it's usually 3x25A; for a single fase it's often 1x35A) and make sure that the meter you choose can handle this...

Lennart

Post by **Digit** » Tue Apr 07, 2009 7:48 pm

Ik heb de Eltako WSZ12E-65A. Zie http://www.hekkers.net/domotica/docs/El ... 2E-65A.pdf . Is wel wat duurder dan die in het hierboven genoemde topic; destijds rond de 120 euro geloof ik.

Post by **Antoon** » Wed Apr 08, 2009 2:06 pm

I am also looking for a three fase meter with S0 output.
Today I received the price for the Eltako (+/- 200 euro)
That is a lot of money so I search for a alternativ and found this one.

http://www.kwhmeter.nl/N_frame.html?htt ... p_8-1.html

Should this work with the RFXPulse?

- Antoon

<h6>

Post by **Willem4ever** » Wed Apr 08, 2009 10:43 pm

I'm using the Eltako as well (well not actually, but very soon). Not sure how reliable the el cheapo meters are

Got around to install my RFXpulse unit which I collected yesterday at Petronics. I ordered a Reflective-Optical sensor with the device to measure my gas usage. At first it wasn't counting correctly, after opening the box the reason became clear, jumpers were set to zero debounce time. After changing to default settings it was working fine. Next stept is to connect my Eltako.